Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Snakes”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed1988

Venomous snake bites in Italy: epidemiological and clinical aspects.

From 1980 to 1984, a total of 2,329 people who alleged that they had been bitten by venomous snakes were admitted to 292 Italian hospitals having first aid stations. Three died. Most patients (62%) did not show any symptomatology of envenomation. The epidemiological and clinical aspects of 286 patients, out of 885 exhibiting signs and symptoms of snake bite envenomation, have been studied. The symptoms and signs were: oedema, gastro-intestinal symptoms, pain at the site of the bite, respiratory distress, leucocytosis, CNS depression, shock, fever, cyanosis, exanthema, ecchymoses, incoagulable blood, lymphangitis, melaena, thrombocytopenia, haematuria, and ophthalmoplegia. The bites were located only in the upper or lower limbs. Most were caused by Vipera aspis. The severity of envenomation of the 286 affected patients were: 45% minor, 30% mild, 14% moderate, 8% severe and 1% fatal. Most bites occurred in August. The commonest treatment before and during hospitalization was anti-venin.

Adult↗
PubMedDate not supplied

The five-ringed brown snake, Pseudonaja modesta (Gunther): report of a bite and comments on its venom.

The first case report of systemic evenomation by the five-ringed brown snake, Pseudonaja modesta, is presented. The patient had mild general symptoms of envenomation only, with no coagulopathy or evidence of paralysis. Data on P. modesta venom is presented, which shows an absence of a coagulant component in this venom. The venom gives a positive reaction to brown snake venom in the CSL Venom Detection Kit.

Animals↗
PubMed1980

Major coagulopathy and "nonpoisonous" snake bites.

Two florid examples of disseminated coagulopathy following the bite of a rear-fanged snake (normally considered "nonvenomous") are reported. The posibility of clinically significant cases of snakebite envenomation due to "harmless" snakes in the United States is raised because of the diagnostic and therapeutic implications.

Antivenins↗
PubMed1980

Clinical features of twig snake (Thelotornis capensis) envenomation.

A case of disseminated intravascular coagulation in a 13-year-old-boy caused by a bite from a twig snake (Thelatornis kirtlandii capensis) is described. The coagulant enzyme was found to be a single-chain mole-activate prothrombin and factor X as well as weakly accelerating fibrinolysis. Its action on synthetic chromogenic substrates is described. Boomslang antivenom was unable to block twig snake venom, and the implications of this as regards treatment are discussed.

Adolescent↗
PubMed1996

Clinical trial of intramuscular anti-snake venom administration as a first aid measure in the field in the management of Russell's viper bite patients.

Efficacy of intramuscular anti-snake venom administration immediately after bite as a first aid measure in the field followed by standard hospital management versus standard hospital management alone in the therapy of Russell's viper bite patients was studied. There was a definite reduction in the number of patients with systemic envenomation, complications following disseminated intravascular coagulation and in fatality rate of Russell's viper bite victims who had received first aid intramuscular anti-snake venom prior to hospitalization when compared with those who had not.

Adult↗
PubMed1980

Modified snake venom in amyotrophic lateral sclerosis. Lack of clinical effectiveness.

Diverse observations including neurological examination, manual muscle testing, quantitative electromyography, videotape esophagrams, and pulmonary function tests were used in a double-blind study evaluating the use of detoxified snake venoms as modified neurotoxin in 64 patients with amyotrophic lateral sclerosis (ALS) treated for six months. Transient periods of improvement were more common in the patients who received placebo. This study did not demonstrate any benefit from administration of modified snake venom to patients with ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1997

Afferent and efferent connections of the nucleus sphericus in the snake Thamnophis sirtalis: convergence of olfactory and vomeronasal information in the lateral cortex and the amygdala.

This paper is an account of the afferent and efferent projections of the nucleus sphericus (NS), which is the major secondary vomeronasal structure in the brain of the snake Thamnophis sirtalis. There are four major efferent pathways from the NS: 1) a bilateral projection that courses, surrounding the accessory olfactory tract, and innervates several amygdaloid nuclei (nucleus of the accessory olfactory tract, dorsolateral amygdala, external amygdala, and ventral anterior amygdala), the rostral parts of the dorsal and lateral cortices, and the accessory olfactory bulb; 2) a bilateral projection that courses through the medial forebrain bundle and innervates the olfactostriatum (rostral and ventral striatum); 3) a commissural projection that courses through the anterior commissure and innervates mainly the contralateral NS; and 4) a meager bilateral projection to the lateral hypothalamus. On the other hand, important afferent projections to the NS arise solely in the accessory olfactory bulb, the nucleus of the accessory olfactory tract, and the contralateral NS. This pattern of connections has three important implications: first, the lateral cortex probably integrates olfactory and vomeronasal information. Second, because the NS projection to the hypothalamus is meager and does not reach the ventromedial hypothalamic nucleus, vomeronasal information from the NS is not relayed directly to that nucleus, as previously reported. Finally, a structure located in the rostral and ventral telencephalon, the olfactostriatum, stands as the major tertiary vomeronasal center in the snake brain. These three conclusions change to an important extent our previous picture of how vomeronasal information is processed in the brain of reptiles.

Afferent Pathways↗
PubMed1998

Cell dynamics in the embryonic and postnatal vomeronasal epithelium of snakes.

This review will discuss changes observed in the cell dynamics of the vomeronasal epithelium (VNE) of snakes during embryonic and postnatal growth. Recent work suggests that neuronal differentiation occurs early in VNE development. We have used an antibody to an evolutionarily conserved peptide sequence (the PSTAIRE region) in a family of cell cycle regulatory proteins, the cyclin-dependent kinases, to identify neuronal precursors in the embryonic and postnatal VNE. During prenatal development, the location of neuronal precursors changes in the VNE. Significant postnatal changes occur in cell proliferation in the VNE (as determined by 3H-thymidine autoradiography) and possibly in the larger complement of VNE receptor cell precursors (as determined by anti-PSTAIRE staining). A model is proposed for changes in cell proliferation and death during embryonic development and postnatal maintenance and senescence in VNE of snakes, which may be applicable to the VNE and olfactory epithelium of other vertebrates.

Animals↗
PubMed1999

Comparative morphology of the cloacal scent gland in snakes (Serpentes: Reptilia).

The histology of the cloacal scent gland, or anal gland, was examined from a diverse group of 50 snakes. Extensive interspecific morphological variation was observed in the general structure of the gland and the glandular epithelium. Morphological variants were quantitatively scored from eight features: lobate nature of the gland; septa in the glandular epithelium; glandular epithelium having a rough or irregular outer surface; glandular epithelium having a rough or irregular inner surface; thickness of the glandular epithelium; PAS reactivity in the glandular epithelium; Periodic Acid-Schiff reactivity in the secretory product; and relative size of the cloacal scent gland. The distribution of the encoded morphological variation was compared to an established phylogeny for snakes and used as the basis for a cluster analysis. In both cases there was no apparent relationship between phylogeny and the morphological variation of the cloacal scent gland.

Animals↗
PubMed1978

The effect of group implosive therapy on snake phobias.

Snake phobic Ss in groups of 10 were presented with a verbal fantasy similar to those used in individual Implosive Therapy (IT) in order to explore the adaptability of the procedure to group use. A single 25-minute implosive presentation of the same material on audio tape was effective in reducing snake phobias in about the same percentage of Ss as individual IT. It was concluded that IT can be adapted to group use, but that care should be taken to ensure an opportunity for extinction to occur through repeated presentation of the fantasy material.

Animals↗
PubMed2000

Interventions for preventing reactions to snake antivenom.

BACKGROUND: Antivenom is used to neutralise snake bite toxins in people showing evidence of envenomation. It is made from animal sera, and adverse effects, including life threatening anaphylaxis, are common. OBJECTIVES: To assess the effects of drugs given routinely with snake antivenom to prevent adverse effects. SEARCH STRATEGY: Cochrane controlled trials register; contact with researchers in the field. SELECTION CRITERIA: Randomised and quasi-randomised trials testing routine adrenaline (epinephrine), antihistamines, or corticosteroids. DATA COLLECTION AND ANALYSIS: The two authors applied the inclusion criteria, assessed trial quality, and extracted the data. We sought additional data from trialists where required. MAIN RESULTS: One trial in Sri Lanka (n = 105) giving adrenaline with polyspecific antivenom showed fewer adverse reactions in the adrenaline group, and this effect was preserved when stratified for severity. One trial in Brazil (n = 101) using three types of Bothrops antivenom showed no benefit of antihistamine drugs. REVIEWER'S CONCLUSIONS: Routine prophylactic adrenaline for polyvalent antivenom known to have high adverse event rates seems sensible, based on this one trial. If clinicians believe local factors do not justify routine adrenaline, then they should test their belief in a randomised trial. Antihistamine appears to be of no obvious benefit in preventing acute reactions from antivenoms.

Antivenins↗
PubMed1990

Further serial transmission electron microscopy studies of auditory hair cell innervation in lizards and in a snake.

Auditory hair cells of three lizard and one snake species were studied by serial transmission electron microscopy (TEM) sections of two unidirectional hair cells (UHC) and two bidirectional hair cells (BHC) and by nonserial section montages of each entire papilla cut at 2-microns intervals across the papillar width. The unidirectional hair cell region of the agamid lizard, Acanthosaura crucigera, lacked efferent innervation. Another agamid lizard, Agama agama, studied by nonserial section only, also lacked efferent innervation to the UHC. Afferent innervation to both the UHC and BHC of Acanthosaura was primarily exclusive (each nerve fiber innervates only one hair cell), although an occasional nerve fiber innervated two hair cells. Both the UHC and the BHC of the anguid, Celestus costatus, were exclusively innervated. Both hair cell types of the varanid, Varanus exanthematicus, were nonexclusively innervated (all afferent nerve fibers innervate two or more hair cells). The auditory papilla of the colubrid snake, Elaphe obsoleta, has only one type of hair cell and each is nonexclusively innervated. The numbers of afferent and efferent nerve fibers and of afferent synapses are presented in tabular form.

Animals↗
PubMed1980

Ascending projections of the dorsal column in a garter snake (Thamnophis siritalis): a degeneration study.

Ascending axons in the dorsal column of garter snakes were examined following hemisection of the spinal cord at segment levels 2, 3, 4, 11, 13, and 31. After postoperative survival periods of 11 to 28 days, sections of the spinal cord and brain were processed with a silver method to demonstrate degenerated axons and preterminals. The study demonstrated that most ascending degenerated axons are located in the outer half of the dorsal column. The somatotopic pattern of ascending fibers is evident, whereby dorsomedial fibers are primarily of caudal origin and the more dorsolateral axons are from rostral cord segments. Rostral to segment 31, all spinal segments appear to project to a strip of dorsal column adjacent to the dorsal median septum. From the septum, axons descend to terminate somatotopically on cells of the nucleus of Bischoff located caudal to the obex of the medulla. Dorsal column degeneration ascends to the level of the dorsal column nuclei, where most fibers terminate. Degeneration from caudal cord segments terminates on caudo-medial cells of the dorsal column nuclei, while rostral cord segments project to rostro-lateral cells. The dorsal column nuclei consist of an expanded lateral part between tractus descendens trigemini and the vago-solitary complex, and a contiguous, thin medial lamina of cells dorsal and medial to the vagal nuclei. The somatotopic pattern of degeneration in the dorsal column nuclei, probably of dorsal root origin, follows the mammalian organization, which suggests that the garter snake has primitive nuclei gracilis and cuneatus. Other terminal sites of degenerating fibers, although probably of spinal gray origin, are nucleus commissura infima, nucleus descendens vestibuli, and area postrema.

Animals↗
PubMed1975

Corticoseptal projections in the snakes Natrix sipedon and Thamnophis sirtalis.

The projections of the cerebral cortex upon the septum in water snakes (Natrix sipedon) and garter snakes. (Thamnophis sirtalis) were studied with the Fink-Heimer degeneration techniques. Two cortical areas send major projections to the septum. Medial cortex projects bilaterally to the dorsal portion of the precommissural septum along its full rostrocaudal extent. The ipsilateral projection is more massive than the contralateral one. Dorsal cortex projects ipsilaterally to a column within the septum which is present dorsally, caudal to the level of the anterior commissure, but shifts ventrally as the septum is followed rostrally. Lateral cortex may send a sparse projection to the ipsilateral ventral septum.

Animals↗
PubMed1988

Distribution of dopamine immunoreactivity in the forebrain and midbrain of the snake Python regius: a study with antibodies against dopamine.

The distribution of dopamine (DA) immunoreactivity in the forebrain and midbrain of the ball python, Python regius, was studied by using recently developed antibodies against DA. In order to determine general and species-specific features of the DA system in reptiles, we have selected the ball python as a representative of a reptilian radiation that hitherto has not been the subject of (immuno)histochemical studies. Dopamine-containing cell bodies were found around the glomeruli and in the external plexiform layer of both the main and accessory olfactory bulb, but not in the telencephalon proper. In the diencephalon, DA cells were observed in several parts of the periventricular hypothalamic nucleus, in the periventricular organ, the ependymal wall of the infundibular recess, the lateral hypothalamic area, the magnocellular ventrolateral thalamic nucleus, and the pretectal posterodorsal nucleus. In the midbrain, DA cells were found in the ventral tegmental area, the substantia nigra, and the presumed reptilian homologue of the mammalian A8 cell group. Dopaminergic fibers and varicosities were observed throughout the whole brain, particularly in the telencephalon and diencephalon. The nucleus accumbens, striatum, olfactory tubercle, and nucleus of the accessory olfactory tract appear to have the most dense innervation, but the lateral septal nucleus, the dorsal ventricular ridge, and the nucleus sphericus also show numerous DA-containing fibers and varicosities. Except for the lateral cortex, cortical areas are not densely innervated by DA fibers. The DA system of the snake Python regius shares many features with that of lizards and turtles as determined with the same antibodies. The taxonomically close relationship between lizards and snakes, which together constitute the Squamata, is reflected in a similar distribution of DA fibers and varicosities to the dorsal ventricular ridge and the lateral cortex, and in the limited number of CSF-contacting DA neurons in the hypothalamus.

Animals↗
PubMed1991

Incorporation of 3H-thymidine in the embryonic vomeronasal and olfactory epithelial of garter snakes.

Previous studies have shown that the vomeronasal and olfactory epithelia of adult vertebrates provide good models for studying normal neuronal turnover and regeneration in response to axotomy. However, little is known about the cell dynamics in the embryonic vomeronasal and olfactory epithelia or the origins of different cell types in these structures. By using 3H-thymidine autoradiography, both in vivo and in vitro, the origins of receptor and supporting cells and the survival of labelled cells in the embryonic vomeronasal and olfactory epithelial of garter snakes were examined. The results of this study suggest that the receptor and supporting cells of both epithelial arise from separate stem cells and that two subpopulations of stem cells exist for receptor cells in the embryonic vomeronasal epithelium. One subpopulation generates cells that migrate through the receptor cell columns, while another subpopulation remains at the base of the epithelium for approximately 50 days. Although it is unclear how long receptor cells in the embryonic olfactory epithelium survive, the results of this study suggest that they survive at least 37 days and may survive over 56 days. In addition, the development of these sensory epithelia appears different in early versus late embryos, and regeneration in the vomeronasal and olfactory epithelia of adult garter snakes appears similar to development during late gestation. Cells in the developing receptor cell layer of the olfactory epithelium lose their ability to incorporate 3H-thymidine before those in the vomeronasal epithelium, suggesting that the onset of neuronal maturation occurs earlier in the olfactory epithelium than in the vomeronasal epithelium.

Animals↗
PubMed1991

Incorporation of 3H-thymidine in telencephalic structures of the vomeronasal and olfactory systems of embryonic garter snakes.

Previous studies have shown that the vomeronasal and, possibly, olfactory systems are functional in newborn garter snakes. However, little is known about neurogenesis in these chemosensory pathways. In the companion paper, we describe the embryonic growth of the sensory epithelia for both the vomeronasal and olfactory systems. In the present study, we examine neurogenesis in the telencephalic structures of these chemosensory systems by using 3H-thymidine autoradiography (ARG). The majority of neurogenesis appears to occur before birth in the accessory and main olfactory bulbs and their principal projection sites, the nucleus sphericus and lateral cortex, respectively. The data suggest that some postnatal neurogenesis may occur in the accessory and main olfactory bulbs and in the nucleus sphericus. Although the neuronal constituents of the accessory and main olfactory bulbs appear to mature concurrently, those of the lateral cortex appear to mature before those of the nucleus sphericus. Along with previous findings, this latter result supports the hypothesis that the olfactory system develops before the vomeronasal system in garter snakes. There appears to be a rostral to caudal gradient of neurogenesis within the mural layer of the nucleus sphericus. However, an "outside to inside" gradient of neurogenesis was not observed in the mantle layer of the lateral cortex, as described for other reptiles. Similarities and differences observed by other investigators in other reptilian species and mammals are discussed.

Animals↗
PubMed1989

Development of antipredator responses in snakes: IV. Interspecific and intraspecific differences in habituation of defensive behavior.

Habituation of defensive attacks directed toward a threatening stimulus was investigated in neonatal garter snakes. The focus of the experiments was on differential effects of a simple experimental process in relation to species, litter, sex, and individual. In Experiment 1 newborn Thamnophis melanogaster from four liters and newborn Thamnophis butleri from three liters were given daily tests in which snakes were confronted with a nonmoving and moving human hand. Over five successive test days the T melanogaster neonates showed a decline in number of strikes directed toward the stimuli. When retested 10-13 days later the animals showed significant response recovery. Although some of the T? butleri newborns demonstrated significant habituation, there was no overall habituation of strike scores in this species. The T? melanogaster had high strike scores, more rapid habituation to moving than nonmoving stimuli, and significant liter differences in habituation rates. The T? melanogaster, but not the T? butleri neonates, showed significant habituation of flight responses over the five tests. In T? butleri, but not T? melanogaster, males were more prone to attack than were females. In both species there were large differences in both overall strike scores and habituation rates of individual newborn animals. In Experiment 2, T? melanogaster 2-months old, were tested for short-term habituation to either a moving or nonmoving stimulus for 10 successive tests on one day. Habituation of strikes was similar to both stimuli, but more animals confronted with the moving stimulus showed an initial increase in strikes, lending support to the dual-process theory of habituation. As in Experiment 1, there were large individual differences in habituation rates. The results are discussed in terms of the ecological and methodological implications for developmental studies.

Aggression↗